Hydraulic motor with wide vane and duplicate exhaust ports and special seals



P 1, 1.959 c. LUDWIG ET AL 2,902,009

HYDRAULIC MOTOR WITH WIDE VANE AND DUPLICATE V EXHAUST PORTS AND SPECIAL SEALS Filed Feb. 16; 1956 7 2 Sheets-Sheet 1 Charles H. eler m ATTORNEYS B red e man 5';

Sepbl, 1959 c LUDWIG ETAL' A 2,902,009

HYDRAULIC MOTOP K WITH WIDE VANE AND DUPLICATE Filed Feb. 16, 1956 EXHAUST PORTS AND SPECIAL SEALS I 2 Sheets-Sheet 2 Ua/I'Z Ludwig 3 -1- 32 hwreslilflweler 30 BY fr d R-Deedmanfi 1 0 9110 ATTORNEYS United States Patent HYDRAULIC MOTOR WITH WIDE VANE AND DUPLICATE EXHAUST PORTS AND SPECIAL SEALS Carl Ludwig, Charles H. Wheeler, and Alfred R. Deedman, Canton, Ohio, assignors, by niesne assignments, to Ex-Cell-O Corporation, a corporation of Michigan Application February 16, 1956, Serial No. 565,967

'4 Claims. (Cl. 121-97) The invention relates to oscillating type hydraulic motors in which the shaft is provided with a radially disposed vane adapted to be oscillated back and forth within the motor housing from one side of a fixed shoe therein to the opposite side thereof.

In hydraulic motors of this general character, the shaft is abruptly stopped at the end of each stroke by contact of the vane with the stationary shoe, causing a considerable impact due to the high pressure fluid operating the motor.

Also, because of the necessary mechanical clearances required between the working parts of the motor, and the high fluid pressure maintained within the motor housing, difliculty has been experienced in preventing oil leakage at these points, as well as between the stationary members of the housing.

It is therefore an object of the invention to provide a hydraulic motor structure which overcomes the abovementioned disadvantages and difficulties.

Another object is to provide a hydraulic motor having means for cushioning the vane at the end of each stroke.

A further object is to provide such a cushioning means comprising a relatively wide vane and a spaced pair of combination inlet-outlet ports in the housing on each side of the stationary shoe.

A still further object is to provide a hydraulic motor of the character referred to, in which the vane is adapted to shut off one exhaust port near the end of each stroke, requiring all of the fluid to exhaust through the other exhaust port, which is equipped with a controlled orifice valve.

Another object of the invention is to provide such a hydraulic motor in which the stationary shoe is recessed into the motor housing or body and rigidly attached thereto by cap screws.

A further object is to provide a hydraulic motor of this type in which special seals are provided, operated by the fluid pressure within the housing.

A still further object is to provide such a hydraulic motor with special back-up seals operated by fluid pressure from outside the housing.

Another object is to provide a rubber O-ring with pressure applied externally to the back of the O-ring to provide .low friction between the shaft and the heads of the housing, allowing greater tolerance between these parts.

A further object of the invention is to provide a hydraulic motor of this type, having a rubber O-ring seal of the character referred to, having a drain back to the tank to relieve pressure at the O-ring.

These and other objects, apparent from the drawings and following description, may be attained, the above described difliculties overcome and the advantages and results obtained, by the apparatus, construction, arrangement and combinations, sub-combinations and parts which comprise the present invention, a preferred embodiment of which, illustrative of the best mode in which applicants have contemplated applying the principle, be-

2,902,009 Patented Sept. 1, 1959 ing set forth in detail in the following description and illustrated in the accompanying drawings.

The invention may be described in general terms as comprising a housing or body formed of two similar heads attached to opposite ends of an annular housing member, with sealing means therebetween. A shoe or barrier is fixed within the housing, being set into a recess in the annular member of the housing and attached thereto by socket-head cap screws.

The motor shaft is located axially through the housing and journalled in bearing portions formed upon the heads of the housing, an enlarged central portion of the shaft being in running contact with a bronze-tipped inner end of the shoe. A central, longitudinally disposed groove is located entirely around the shoe, and a rectangular rubber ring is located in this groove and backed up on either side with rectangular, fiat, high temperature plastic sealing members, forming a liquid-tight seal between the shoe, the annular member and heads of the housing and the shaft.

Ports are located through the housing on either side of the shoe and a second port is spaced from each of the firsementioned ports, pipes connecting all of said ports to an oil pump, with suitable valves arranged to optionally connect either pair of ports to the pressure side of the pump and the other pair of ports to the return side of the pump.

A radial vane is fixed upon the shaft, the arcuate outer surface thereof being in running contact with the inner walls of the housing, and being of such width that as the shaft approaches each end of the stroke, the first port on that side is shut off, causing all of the oil to exhaust through the other port, which is provided with a controlled orifice valve, producing a cushioning effect upon the shaft. The vane is provided with sealing means similar to that upon the shoe.

Novel sealing means are provided for the shaft, comprising rubber O-rings located in grooves in the housing and backed up with high temperature plastic rings, external oil pressure being applied to the O-rings, and drains communicating with said sealing means for draining the oil therefrom back to the tank.

The invention having been described in general terms, reference is now made to the accompanying drawings illustrating a preferred embodiment of the invention, in which;

Fig. 1 is a transverse sectional view through an oscillating hydraulic motor embodying the invention, showing the vane at one end of a stroke and in contact with one side of the shoe;

Fig. 2 is a longitudinal sectional view through the hydraulic motor shown in Fig. 1, with the vane inan intermediate position, located substantially diametrically opposite to the shoe;

Fig. 3 is a detached elevation of the substantially U- shape rubber O-ring seal for the vane;

Fig. 4 is a transverse section of an intermediate portion of the O-ring, taken as at 4-4, Fig. 3;

Fig. 5 is a section of a corner portion of the O-ring, taken as on the line 5-5, Fig. 3;

Fig. 6 is a detached perspective view of one of the plastic back-up members of the vane seal;

Fig. 7 is a detached elevation of the rectangular rubher O-ring seal for the shoe; 7

Fig. 8 is a transverse section through an intermediate portion of the O-ring shown in Fig. 7, taken as on the line 88, Fig. 7;

Fig. 9 is a section through a corner of the O-ring shown in Fig. 7, taken as at 9-9, Fig. 7; and,

Fig. 10 is a detached perspective view of one of the plastic back-up members of the shoe seal.

Particular reference is now made to the embodiment of theinvention illustrated,.in.which similar numerals -indicate'lik'e' parts throughout the several views. The cylinder housing or body of the motor comprises the annular member and the heads 16 connected to opposite ends thereof in any conventional manner, as by the cap screws 17.

The joints between these members are sealed by the rubberiQ-rings 1 8 located in the annular grooves 19 in the oppositefaces' of the annular member 15 and adapted to be'pressed into sealing contact with the inner surfaces cf the heads b'y'oil pressure from within the housing, thus preventing leakage of oil.

"An outwardly disposed bearing portion 20 is formed upon each head 16. The motor shaft 21 is located axially through the housing and journalled in said bearing portibns 20 of the heads. Preferably, the central portion 22 o f the shaft may be of larger diameter, as best shown in Fig.2.

A stationary shoe or barrier 23 is connected to the interior of the housing, as in usual practice in this general type of hydraulic motor. In the present embodiment, this shoe is shown as set into a recess 24 in the annular member 15 of the housing, and rigidly attached thereto by socket-head cap screws 25, located through suitable bores in the annular member and shoe. Pipe plugs 26 may be screwed into the outer ends of the bores in the housing, on top of the cap screws.

' The end of the shoe 23 closest to the shaft is preferably tapered, as indicated at 27, and tipped with bronze or the like as shown at 28, preferably a bronze sold under the trademark of Tobin Bronze, so as to provide substantially a running fit with the enlarged central portion 2 2'of the shaft In o'rder'to prevent the extreme oil pressure within the housing from causing leakage'of oil from one side of the shoe 23 to the other side thereof, a seal is located centrally, entirely around the shoe, between the housing walls and the shaft. For this purpose, a centrally located groove 29 is formed entirely around the shoe, and a rectangular rubber ring 30 is located therein and backed up on either side by a rectangular flat sealing member 31 formed of heat-resisting plastic material. "Polytetrafluoroethylene is the preferred plastic material forthese back-up members. This material is commonly sold under the trademark of Teflon, and for the sake'of brevity it will be so referred to throughout the specification.

Each 'ofthe rubber rings 30 is round throughout its entire cross-sectional area, excepting at the corners, where it is flattened on each side, as indicated at 32, and provided with square corners 33, as shown in Figs. 7 and 9.In order to permit the plastic back-up members 31 to be inserted into the groove 29 of the shoe, one side of each back-up member is cut through on a bias, as indicated at34 in Figs. 2 and 10. i 'A radial vane 35 is fixed to the shaft, as by welding, as indicated at 36, the inner end of the vane being bevelled' on 'each side, as shown at 37, to receive the weld metal. The arcuate outer surface 38 of the vane is of considerable length, as best shown in Fig. 2, and has substantially a running fit Within the annular member 15 ofthe housing.

At its center the vane 35 is provided with a groove 33, extending across its outer edge and along both side edges thereof, for receiving sealing means similar to the sealing means of the shoe. This sealing means comprises the substantially U-shape, rubber O-ring 40 and the plastic back-up member 41, asshown in detail in Figs. 3 to 6 inclusive.

' The U-shape rubber O-ring 40 is of circular cross section throughout its entire area, excepting at its corners and the ends of the legs of the U, where it is flattened on both sides as indicated at 42 and provided with square corners 43, as shown in Figs. 3 and 5. Thus oil pressure within the cylinder housing, on either side of the 4 vane, will cause the O-ring 40 to be deformed and pressed against the opposite back-up member 41 providing a liquid-tight seal to prevent oil passing from one side of the vane to the other side thereof.

As in usual practice in hydraulic motors of this general type, ports 44 and 44a are located through the housing on opposite sides of the shoe 23, and connected by pipes 45 and 45a respectively to an oil pump, suitable-valve means (not shown) being located between the ports and the pump for optionally connecting either port with the pressure side of the pump and the other port to the return side or reservoir of the pump, as in customary practice. Thus, either port 44 or 44a may become an inlet port and the other port a discharge or exhaust port, for driving the vane 35 in either direction and thereby rotating the shaft 21 in either direction, as may be desired.

For the purpose of cushioning the shaft as the vane approaches each end of the stroke, and thus eliminating the sudden impact of the .vane against opposite sides of the shoe, a second port is located on each side of the shoe, at points spaced from the ports 44 and 44a,

These second or auxiliary ports are indicated at 46 and 46a, located at points spaced from the ports 44 and 44a respectively, and are connected as by pipes 47 and 47a respectively, with the usual oil pump, the valve means above referred to being arranged to optionally connect either port 46 or 46a to the same side of the pump as the ports 44 or 44a respectively.

The ports 46 and 4 6a are so spaced from the respective ports 44 and 44a, that the distance therebetween is considerably less than the length of the arcuate outer surface. 38 of the vane, so that as the vane moves in either direc: tion, upon approaching the end of the stroke the auxiliary port 46 or 46a will be shut off by the vane passing over the same, causing all of the oil on the discharge side of the vane to be exhausted through the corresponding port 44 or 44a, as the case may be, thus cushioning the vane and shaft. 7 i 4 V In order to further increase this cushioning effect, controlled orifice valves 48 and 48a may be located in thepipes 45 and 45a connected to the ports 44 and 44a respectively. These valves may be adjusted to produce. any desired cushioning effect.

it .will be obvious that as the orifices in these valves are decreased the discharge of oil therethrough will be correspondingly slowed down. In like manner, at the start of each stroke, oil will be admitted only through the corresponding port 44 or 44a, and the shaft will not reach maximum speed until the corresponding auxiliary port 46 or 46a is uncovered by the vane 35 passing downward beyond the same, because oil is also admitted to the cylinder housing, above the vane, from the corresponding auxiliary port 46 or 46a.

Because of the mechanical clearance between the enlarged portion 22 of the shaft and the adjacent walls of the housing, fluid under pressure tends to equalize between the chambers 49 and 50 on opposite sides of the vane 35, by leaking through this clearance from the pressure side to the exhaust side of the vane. 3

Furthermore, the mechanical clearances between the journal portions of the shaft 21 and the bearing POI-1 tions 20 of the heads, will tend to permit fluid under pressure to be forced through said clearances and to leak aroundeach end of the shaft. v

For the purpose of preventing such leaking of oil from one chamber to the. other, and between the shaft and the bearing portions of the heads, a novel sealing means is provided, operated by external oil pressure, to provide low friction sealing between the shaft and heads, thus allowing greater tolerance.

This scaling is accomplished by providing a concentric annular groove 51 in the inner faceof each head 16, at the ends of the enlargement 22 of the shaft. A rubber v O-rin'g 52 is located in each groove 51 and backed up by a preferably slightly beveled Teflon ring 53.

' Oil passages 54 are provided in the heads 16, communicating with the grooves 51 therein. These oil passages are adapted to be connected to an external source of oil under pressure, whereby the O-rings 52 ,will be deformed, pressing the Teflonback-up rings 53 into sealing contact with the ends of the enlarged portion 22 of the shaft.

The journal portions of the shaft 21 are sealed by providing annular grooves 55 in the bearing portions 20 of the heads, surrounding the journal portions of the shaft near the outer ends of the bearings. Rubber O-rings 56 are located in the grooves 55, and backed up on each side by substantially flat Teflon rings 57. A drain 58 communicates with each groove 55 and is adapted to be connected to a tank or reservoir of the external oil pressure means, so as to relieve pressure at the O-rings. 7

It will be understood that due to the high pressure of the oil admitted to the interior of the housing for oscillating the shaft 22, there is a tendency for the oil to be forced out of the cylinder around the journal portions of the shaft 21 between the shaft and the bearing openings in the bearing portions 20 of the heads.

This oil will build up under pressure in the grooves 55 within which the sealing means 56-57 is located tending to reduce the effectiveness of the sealing means. For this reason the drains 58 are connected to the sealing grooves 55 so as to relieve this oil pressure and permit the oil to drain from the sealing grooves 55.

As shown in Fig. 2, an annular groove 59 may be formed in each bearing portion 20, between the enlarged portion of the shaft 22 and the corresponding sealing groove 55, and longitudinally disposed recesses 60 may be formed in the bearing portions communicating with the grooves 59. This provides means for retaining a small amount of oil at these points for lubricating the journals of the shaft.

From the above, it will be obvious that the disadvantages and difiiculties present in hydraulic motors of this general type are overcome. The provision of auxiliary ports on opposite sides of the shoe, and the provision of the wide vane of greater width than the distance between the ports on each side of the shoe, produces a cushioning of the shaft as it approaches each end of a stroke, thus eliminating the objectional impact of the vane against the shoe at the end of each stroke. The provision of a controlled orifice valve in each main port permits of adjusting the cushioning effect as may be necessary or desirable.

The improved sealing means for the shoe and the vane prevent the forcing of oil from one chamber of the cylinder to the other, around these ports. And also, the provision of the sealing means for the shaft, operated by external pressure, prevents oil from being forced around the shaft from one chamber to the other.

The sealing means around the journals of the shaft, with means for drawing oil back to the tank, provides a low friction sealing between the shaft and the heads, thus allowing greater tolerance. Furthermore, the O-ring seals between the heads and the annular member of the cylinder housing prevent oil leakage between these parts.

In the foregoing description, certain terms have been used for brevity, clearness and understanding, but no unnecessary limitations are to be implied therefrom beyond the requirements of the prior art, because such words are used for descriptive purposes herein and are intended to be broadly construed.

Moreover, the embodiments of the improved construction illustrated and described herein are by way of example, and the scope of the present invention is not limited to the exact details of construction.

Having now described the invention or discovery, the construction, the operation, and use of preferred embodiments thereof, and the advantageous new and useful results obtained thereby; the new and useful construction, and reasonable mechanical equivalents thereof obvious to those skilled in the art, are set forth in the appended claims.

We claim:

1. A hydraulic motor comprising a cylindrical housing including an annular member and heads attached to opposite ends thereof, a shaft located axially through the housing and journalled in said heads, a shoe mounted in the housing and having a running fit with the shaft, a solid vane mounted on the shaft and having a running fit within the housing, two main ports in the housing,

- one adjacent to each side of the shoe and auxiliary ports,

pipes connected to said main ports and auxiliary ports in the housing spaced from the main ports for alternately admitting fluid to the housing through the main and auxiliary ports on one side of the shoe and discharging fluid through the main and auxiliary ports on the other side of the shoe, controlled orifice valves in the pipes connected to said main ports, there being a centrally located groove in the outer and side surfaces of the vane, and sealing means in said groove, the length of said vane being such that when the leading end of the vane contacts one side of the shoe the adjacent auxiliary port will be shut off by the vane at a point between said leading end of the vane and said sealing means, and the corresponding main port will be at least partially open.

2. A hydraulic motor comprising a cylindrical housing including an annular member and heads attached to opposite ends thereof, a shaft located axially through the housing and journalled in said heads, a shoe mounted in the housing and having a running fit with the shaft, a solid vane mounted on the shaft and having a running fit within the housing, two main ports in the housing, one adjacent to each side of the shoe and auxiliary ports, pipes connected to said main ports and auxiliary ports in the housing spaced from the main ports for alternately admitting fluid to the housing through the main and auxiliary ports on one side of the shoe and discharging fluid through the main and auxiliary ports on the other side of the shoe, controlled orifice valves in the pipes connected to said main ports, there being a centrally located groove in the outer and side surfaces of the vane, and sealing means in said groove, the length of said vane being such that when the leading end of the vane contacts one side of the shoe the adjacent auxiliary port will be shut off by the vane at a point between said leading end of the vane and said sealing means, the sides of the shoe and the ends of the vane being so shaped that when either end of the vane contacts either side of the shoe the adjacent main port will be only partially shut off by the vane.

3. A hydraulic motor comprising a cylindrical housing including an annular member and heads attached to opposite ends thereof, a shaft located axially through the housing and journalled in said heads, a shoe mounted in the housing and having a running fit with the shaft, a solid vane mounted on the shaft and having a running fit within the housing, each end of the vane being beveled adjacent the shaft and weld metal located between said beveled portions of the vane and the shaft for rigidly attaching the vane to the shaft, two main ports in the housing, one adjacent to each side of the shoe and auxiliary ports in the housing spaced from the main ports, pipes connected to said main ports and auxiliary ports for alternately admitting fluid to the housing through the main and auxiliary ports on one side of the shoe and discharging fluid through the main and auxiliary ports on the other side of the shoe, controlled orifice valves in the pipes connected to said main ports, there being a centrally located groove in the outer and side surfaces of the vane, and sealing means in said groove, the length of said vane being such that when the leading end of the vane contacts one side of the shoe the adjacent auxiliary port will be shut off 'by the vane at a point between said leading end of 'the vane and said sealing means, and the corresponding main port will be at least partially open.

4. A hydraulic motor comprising a cylindrical housing including an annularrnember and heads attached to opposite ends thereof, a shaft located axially through the housing and journalled in said heads, a shoe mounted in the housing and having a running fit with the shaft, a solid vane mounted on the shaft and having a running fit'within the housing, two main ports in the housing, one adjacent to each side of the shoe and auxiliary ports, pipes connected to said main ports and auxiliary ports in the housing spaced from the main ports for alternately admitting fluid to the housing through the main and auxiliary ports on one side of the shoe and discharging fluid through the main and auxiliary ports on the other side of the shoe, controlled orifice valves in the pipes connected -to said main ports, there being a centrally located groove in the outer and side surfaces of the vane, and sealing means in said groove, the length of said vane being such that when the leading end of the vane contacts one side of the shoe the adjacent auxiliary port Will be shut off by the vane at a point between said leading end of the vane and said sealing means, opposite sides of the shoe being tangentially dis posed and opposite ends of the vane being radiallydisposed so'that-whenueither end ofthe vane contacts-either side of'theshoe there'will be an outwardl'yflared space therehetween communicating with the corresponding main port, thus preventing complete closure of said main port.

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